The present invention relates to a semiconductor structure, and more particularly to a micro fabrication process for a semiconductor structure having novel characteristics which are not attained with prior arts.
It has been theoretically known that semiconductor lasers which exploit the quantum size effect based on a multi-dimensional quantum well structure have characteristics superior to those of conventional quantum well lasers Y. Arakawa and H. Sakaki, Appl. Phys. Lett., Vol. 40, No. 11, (1982) p. 939).
For substantiating this, it has been attempted to photoetch a superlattice and fabricate a quantum wire which is triangular in cross section (P. M. Petroff et al, Appl. Phys. Lett., Vol. 41, October 1982, p. 635).
Besides, a metal wire which is 10 nm wide has been obtained with electron-beam lithography (H. G. Graighead et al, Appl. Phys. Lett., Vol. 42, January 1983, p. 38).
A multiple quantum wire which is ultrafine enough to produce the quantum size effect and the widths, straightness and inter-wire distances of which are uniform is indispensable to novel semiconductor lasers and electronic devices of excellent characteristics. It is accordingly desired to develop a fabrication process which is easy and which is of high reliability.
The prior arts mentioned above do not take industrial production into consideration, and leave it as a problem to establish fabrication technology for the multiple quantum wire having uniform wire widths, straightness and inter-wire distances.